We are headed to LA for Xmas break, 2017. We used Chase Ultimate Rewards points for 3 out of 5 of our flights.
The United flights that I booked cost $470 each. For each flight I needed 37,600 Ultimate Rewards points. Points can be redeemed for travel through the Ultimate Rewards site at a value of .0125 cents per point when you have a Chase Sapphire Preferred card, like I do. ($470/.0125). Unfortunately, I only had enough points at the time for 3 flights and had to pay for 2. (Yikes!) So we only saved $1,400 on these flights. (470 X 3).
Note, since I booked through the Chase site, I will still earn United MileagePlus miles on the flights redeemed with points (and obviously on the 2 flights I paid for) because my travel counts as a paid fare even though I used Chase points to book the flights.
For the 2 flights I paid for, I used my Chase Sapphire Preferred card, as I get 2x Ultimate Rewards points on airline purchases and even one additional points for booking my airfare online through Ultimate Rewards.